1. Field of the Invention
The present invention relates to an reactor for olefin polymerization using a spouted bed and a polyolefin production system, and a process for producing polyolefin such as polyethylene or polypropylene, using them.
2. Related Background Art
A gas-phase polymerization reactor capable of forming a fluidized bed is known as an olefin polymerization reactor to polymerize olefin in the presence of a solid catalyst to obtain polyolefin particles. This reactor is provided with a single-stage gas-phase polymerization reactor consisting of one polymerization stage, a heat exchanger which cools and partly condenses an unreacted-olefin-containing gas recovered from the reactor, so as to remove heat from the interior of the reactor, and a pipe for again supplying the cooled gas and the condensate liquid to the reactor (e.g., cf. Patent Literature 1).
Another known gas-phase polymerization reactor capable of forming a fluidized bed is a multistage gas-phase polymerization reactor partitioned into two or more polymerization stages and configured to move polyolefin particles from an initial stage to a final stage and to supply an olefin-monomer-containing gas from the final stage to the initial stage (e.g., cf. Patent Literatures 2 and 3). An ordinary known device for removal of heat in the multistage gas-phase polymerization reactor is a device with a heat exchanger to lower the temperature of the unreacted-olefin-containing gas recovered from the initial stage of the polymerization reactor, and a pipe to supply the temperature-lowered gas again to the final stage of the polymerization reactor.
Furthermore, the known reactor for olefin polymerization reaction also include reactors for olefin polymerization using a spouted bed (e.g., cf. Patent Literatures 4 and 5) and a known device for removal of heat in the spouted-bed-type olefin polymerization reactors is a device configured to introduce a liquid monomer into a reaction region and remove heat by making use of its evaporation latent heat.